I have a 1998 Jeep grand cherokee laredoXXXXXstraight 6. 4.0 with 150,000 miles on it. Recently drove from Calif. to New York and back. On the way back , in Arkansa, it started to "cough"/cut out on occasion. It happened more and more until it then began to stall at intersections. I thought it was just some bad gas so I went to replace the fuel filter only to find it was in the tank and a whole assembly needed to be replaced. Did not change a thing. 4 different mechanics had several ideas. Even the code shown when plugged in, showed that it was a coil issue. Bought new coil, nothing, pick-up coil, nothing, map sensor, nothing, crank position sensor, nothing, changed all plugs, wires, cap, rotor, nothing still. Dealer said catalytic converter might be clogged. New one in and getting worse. Finally I was told by another mechanic that the main computer, ecm, is probably shot. Just put a new one in last week and drove about 200 miles with no problem. That must be it! No. Last night it just began to putter out and would not start back up. Got towed home. Cranks but nothing else. The very last opinion was that the alarm system has something to do with it as it makes a funny loud chirp about a minute after I turn the car off. I was told there was some kind of way the alarm system causes a shut down. If this is it, I can live without the alarm if I new how to yank it out, cut a wire or?? I am stranded and now can not get to work. Spent over $2,500+, all my savings and nothing! Anybody really know the answer?
Country: United StatesMake: JeepModel: Grand Cherokee LaredoYear: 1998Engine: 4.0
Hello!My name is XXXXX XXXXX X can assist you with your question.Are you saying that the engine currently cranks over but does not start? Does it have spark when cranking it over? If so, does it run on starting fluid?Can you get me the code number in the computer by chance?I will be looking forward to your reply!Amedee
I don't have the device to check for any codes. that was at 2 different mechanics. Hate to have it towed to any if they could not fix it before. It does turn over but it's fuel injection, not sure where to spray starting fluid if I had it. What about the alarm disable possibility?
Hello!Are there any anti theft or security lights on or flashing on the dash with the key on?What color ignition key do you have?Have you tried using another ignition key?
No lights flashing or dash notices. Simple black coating on key with trw alarm button attached with key ring. Other keys say "valet key".
Ok.. I don't think it is an alarm issue unless you have an after market alarm system installed.The engine is cranking over but not stating correct? Does it have spark when cranking it over?
I guess I'll need another person to crank while I pull the coil wire to check for spark. I'll have to wait a while later to do that unless you know another way.
This is what will need to be done. If the engine has spark when cranking over, see it runs on starting fluid. You could just have a fuel delivery concern. If there is no spark when cranking it over, then we check to be sure that the computer is awake with the key on. We do this by checking for 5 volts going to the TPS and MAP sensor with the key.
I do have a volt meter and can check that now. I turn key to on position then pull plug off map sensor? Then where do prongs from volt meter go?
THats correct! Just unplug the connector going to the TPS and or the MAP sensor (you only have to do this check on one of these sensors). Then with a voltmeter, put the black lead on battery ground and the red lead in one of the cavities to get a volt reading from the wires going into the sensor. You can check one at a time. At least one (if not two wires) should have 5 volts.
2 of the wires show a bit over 5 volts. The reason I was pressing the alarm issue is because of the unusual loud chirp 60 seconds after the key is turned off, every time. I thought it would be worth a try to dis connect it.?
It is a possibility. But if this were the case, the engine would not crank over or it would crank over but not have any spark. Thats why it is important to check for spark when cranking it over.
Ok then I'll wait for a helper a bit later and check for spark, then get back to you but, in the meanwhile, maybe we can look at what the proper method is for dis connecting the alarm without causing malfunction to anything else. I'll check spark first then send you the results.
There is no way to disconnect the alarm system on this vehicle. It is built into the computer
Just got back and plenty of spark out of coil. As for fuel, rather than get a ride on a twenty mile round trip to buy starting fluid, maybe disconnecting the fuel line someplace and cranking it for a couple seconds?
Hello!YES.. that will work to check fuel pressure... but then we need to check injector pulse using a noid light. There is two ways the engine gets fuel. The fuel pump pressurizes the fuel rail and the injectors spray gas into the engine when cranking and running. So if it runs on starting fluid, then we know we are missing one of the two. But yes.. you can check one at a time.
Before removing any fuel lines I thought I'd take off the air intake housing from filter and take a look inside throttle area. After cranking I thought I should see or at least smell a little gas. Nothing. Also, there is a needle valve, like that on a tire or air conditioner, on the rigid tube feeding fuel to the injectors. I removed the cap and pushed the pin and noticed that only a tiny drop of fuel came out. Does this mean no pressure? Fuel pump failure? I just put a new one in 3 months ago.
Hello! Yes this means there is no fuel pressure. Your new fuel could just be bad provided it has power to it and fuel in the tank. AMEDEE41094.8124083681
ASE MASTER TECHNICIAN ADVANCED LEVEL SPECIALIST
Just to confirm it, I sprayed the starting fluid and it started right up for a few seconds. I wonder if I could somehow test if power is getting to the pump before going through all that work to get at it inside the tank? I just filled the tank yesterday! Note that I also replaced the fuel pump relay.
Yes.. This sounds like a fuel delivery concern. You would need to check power going to the fuel pump on the power wire with a test light or a voltmeter while cranking the engine over before replacing the fuel pump.